Field of the Invention
The present invention relates to an image processing apparatus, image processing method, and storage medium, and particularly to a technique of reading out and processing additional information from a print product in which information other than image information, for example, voice information, text information, and pieces of information about an image are embedded as additional information in the image.
Description of the Related Art
Conventionally, extensive studies have been made on multiplexing other information associated with an image in image information. Recently, a so-called digital watermark technique is being standardized. This technique multiplexes, in image information of a photograph, painting, or the like, additional information such as the author name and permission/inhibition of the use so that it is difficult to visually discriminate the additional information. The image information is then distributed through a network such as the Internet.
As another application field, there is a technique of embedding additional information in an image in order to specify an output device and its device number from an image output on a print medium, in order to prevent forgery of a banknote, stamp, securities, and the like along with the improvement of the image qualities of image output apparatuses such as a copying machine and printer.
Even a technique of reading out additional information from a digital watermark-embedded print product by using an image capturing device such as a camera is being examined. For example, Japanese Patent Laid-Open No. 2003-348327 proposes a technique of capturing, by a camera-equipped mobile phone, a print product in which the URL of the save location of voice data is embedded as a digital watermark, reading additional information, and at that time, correcting an image distortion arising from a photographing lens.
However, the related art has the following problem.
In a case where a digital watermark is embedded in a wide range of a print product, the entire digital watermark-embedded printed area cannot be captured by one shooting, and needs to be captured separately a plurality of times while moving an image capturing medium such as a camera. However, when the user captures the print product while moving the image capturing device such as a camera held by the hand on the image capturing target, a camera shake may cause to blur the captured image. In particular, the distance between the object and the camera changes during movement, and out-of-focus may occur. This problem cannot be solved by the above-mentioned technique.